Sometimes no admin mail and no registration of a order in backend

[HeidemanMedia]

The problem is solved! i updated the shop from 1.5.6 to 1.5.9 and te bug is fixed

[HeidemanMedia]

Hello,

I have a client whit a Bakery webshop. This webshop runs for almost to years. The problem is sometimes there is no mail to the admin when a order has placed. And now a new order is also not to see in the backend.

Has someone an idea what this problem can be?